1. Field of Invention
This present invention relates generally to improvements in the field of rechargeable batteries, and more particularly to improvements in metal-air batteries, including metal-air fuel cell battery (FCB) systems which have both discharging and recharging modes of operations.
2. Brief Description of the State of Knowledge in the Art
In recent times, metal-air fuel cell battery (FCB) systems have received great recognition for their ability to produce large amounts of electrical power from relatively small size devices. During power generation, a metal-fuel structure such as zinc is positioned over a cathode structure in the presence of an ionically-conducting medium, such as an electrolyte-impregnated gel or electrolyte solution. In accordance with well known principles of electro-chemistry, as electrical power is produced from the system the metal-fuel structure is oxidized. Examples of prior art metal-air FCB systems are disclosed in Applicants"" U.S. Pat. No. 5,250,370 incorporated herein by reference.
In U.S. Pat. No. 5,250,370, Applicant discloses an improved method of and system for recharging oxidized metal-fuel tape used in prior art metal-air FCB systems. During power generation, metal-fuel tape is transported over a stationary cathode structure in the presence of an ionically-conducting medium, such as an electrolyte-impregnated gel. In U.S. Pat. No. 5,250,370, a recharging head is installed downstream from the discharging head for carrying out recharging operations when the metal-fuel tape has been completely oxidized. In order to enable quicker recharging of metal-fuel tape for reuse in FCB discharging operations, the cathode surface of the recharging head is made substantially greater than the cathode surface of the discharging head. While this arrangement allows for recharging of metal fuel tape, it requires a separate recharging head assembly in order to efficiently carry out recharging operations, in an energy efficient manner. This increases the manufacturing cost of the overall system, and containing the head assemblies within a compact housing quite difficult.
In Applicants"" copending U.S. Pat. No. 6,296,960, Applicants disclose a metal-air fuel cell battery system having a hybrid discharging/recharging head assembly for carrying out discharging and recharging operations as required. In this FCB system design, the recharging head assembly is spaced apart from the discharging assembly, for selectively recharging discharged regions of metal fuel tape.
In Applicants"" copending U.S. application Ser. No. 09/074,337, Applicants also disclose a FCB power generation system that produces electrical power by discharging metal-fuel having the form factor of cards and sheets. When the metal-fuel cards are discharged (i.e. oxidized), the metal-fuel cards can be recharged by being reduced by a recharging head assembly provided within the system.
However, despite such advances in rechargeable metal-air FCB systems, prior art metal-air FCB systems, in general, suffer from an number of shortcomings and drawbacks that have made commercial success difficult to attain, namely: (1) some systems and devices employ bi-functional cathode structures which are energy-inefficient and have a relatively short cycle life (e.g. about 40 or so recharging cycles) due to the production of gas bubbles inside the porous cathode structure caused by the recharging action; (2) many systems and devices employ separate recharging head assemblies for recharging metal-fuel structures, which increases the manufacturing cost of the overall system, while containing the head assemblies in a compact housing; (3) some systems employ metal-fuel anode structures having large surface areas which are very difficult to discharge in an uniform manner due to the formation of xe2x80x9cspotsxe2x80x9d during recharging operations which provide places for zinc tree-like structures (referred to as xe2x80x9cdendritesxe2x80x9d) to grow and locations where short-circuiting can occur; (4) some systems and devices employ metal anode structures that undergo significant shape change during recharging operations; (5) some systems and devices employ the electrolyte-pervious metal anode structures from which xe2x80x9cdendritesxe2x80x9d often grow from towards the cathode structures, eventually shorting-out the power cell structure and thus reducing the cycle life thereof; and (6) some systems and devices employ the metal anode structures that undergo densification during repeated recharging and discharging cycles, thus reducing the cycle life of the power cell structures therewithin as well.
Thus, there is a great need in the fuel-cell battery art for alternative ways and means of electrochemically producing electrical power from metal-air fuel cell battery systems as well as recharging the same as needed, while overcoming the shortcomings and drawbacks of prior art technologies known in the fuel-cell battery field.
Accordingly, a primary object of the present invention is to provide an improved system and method of discharging and/or recharging electrochemical battery systems and devices, while avoiding the shortcomings and drawbacks of prior art methodologies.
Another object of the present invention is to provide an improved metal-air FCB system, wherein different types of cathode elements are embodied within an integrated support structure in order to achieve improvements in discharging and/or recharging operations, as well as the overall performance of the electrical power generating systems and devices employing the same.
Another object of the present invention is to provide an integrated cathode structure having a plurality of relatively small cathode elements spatially arranged on a cathode support structure, in combination with a plurality of anode-contacting elements spatially arranged on an anode-contacting element support plate, wherein each cathode element is in spatial registration with one of the anode-contacting elements so as to form either a discharging and/or recharging cell that is independently activatable (i.e. enabled) using a solid-state transistor switching technology under the control of a cell switching controller embodied within an electrical power generating module.
Another object of the present invention is to provide such an integrated cathode structure, wherein control over each cell can be achieved by monitoring the cell voltage and/or current during discharging or recharging operations, and then measuring the voltages and/or currents and comparing the same with reference measures to ensure that a particularly selected power, voltage and/or current control method is being carried out in a desired manner.
Another object of the present invention is to provide such an integrated cathode structure, wherein if any cell has lower than normal voltage value thereacross, then the cell switching controller, can automatically determine (by computation) to skip this section during normal discharge, and after a certain period of time, the cell switching controller can return to recheck the status of the skipped cell and decide to xe2x80x9cfix/repairxe2x80x9d or abandon the same.
Another object of the present invention is to provide such an integrated cathode structure, wherein thinner current conductors can be used to collect the same amount of current within a discharging head assembly.
Another object of the present invention is to provide such an integrated cathode structure which, when used for recharging metal-fuel like structures, enables the recharging power to be evenly distributed among the cathode elements, or in a manner precisely controlled according to feedback signals derived therewhile, so as to achieve uniform recharging and avoidance of dendrite growth, thereby increasing the anode cycle life.
Another object of the present invention is to provide an improved metal-air FCB system, having a hybrid discharging/recharging head assembly which comprises a first array of cathode elements (i.e. segments) that are a disposed on a common support substrate and optimized/designed for use in discharging operations, and a second array of recharging cathode structures also disposed on the common support substrate but optimized/designed for use in recharging operations in order to avoid fast degradation of the cathode and anode elements, while increasing the overall efficiency of the system during discharging and recharging operations.
Another object of the present invention is to provide such improved metal-air FCB system, wherein a first array of anode-contacting elements are provided in spatial registration to the first array of cathode elements (i.e. segments) so as to produce a first plurality of discharging cells for loading metal-fuel material therewithin and generating electrical power therefrom during discharging operations, and a second array of anode-contacting elements are provided in spatial registration to the second array of cathode elements (i.e. segments) so as to produce a second plurality of recharging cells for loading discharged metal-fuel material therewithin and supplying electrical power thereto during recharging operations.
Another object of the present invention is to provide such improved metal-air FCB system, wherein the first and second plurality of discharging and recharging cells are realized within a unity support structure or subassembly, and each discharging cell and/or recharging cell is electronically-controllable in order to carry out any one of a number of power, voltage and/or current control methods under microprocessor control.
A further object of the present invention is to provide such an improved rechargeable metal-air fuel cell battery (FCB) system having both high energy density characteristics as well as improved discharge/recharge cycle lifetimes.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein the first plurality of discharging cells and the second plurality of recharging cells are spatially arranged in the form of a xe2x80x9cmosaic-likexe2x80x9d structure.
Another object of the present invention is to provide such an improved rechargeable FCB system, wherein each discharging-optimized cathode element and each recharging-optimized cathode element in the hybrid discharging/recharging head assembly is switched into operation (i.e. activated) by a programmed microprocessor.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein the xe2x80x9cmosaic-likexe2x80x9d structure is realized within a relatively thin structure and within which a multi-element or single-element metal-fuel card can be disposed for discharging and recharging operations alike.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein the metal-fuel card can be manually or electro-mechanically translated into its discharging configuration as well as its recharging position, for operation during discharging and recharging operations, respectively.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein the metal-fuel card can be electro-mechanically forced to undergo micro-displacements, relative to the recharging-optimized cathode elements, along the longitudinal direction of the recharging cells during recharging operations, in order to inhibit growth of dendrite formations along the metal fuel elements or regions being recharged.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein discharging operations and recharging operations can be carried out at different times or simultaneously, as the application or situation may require.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system for installation within the battery storage compartment formed in a cellular phone, laptop computer system, or any other electrical power consuming device.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein the use of special bi-functional electrodes are completely avoided, while producing conditioned electrical power for driving electrical loads under optimized discharging conditions, as well as receiving conditioned electrical power for recharging discharged metal-fuel structures under optimized recharging conditions.
Another object of the present invention is to provide an improved rechargeable metal-air FCB system, wherein the anode elements are positioned and vibrated relative to the recharging-optimized cathode elements along the metal-fuel card during recharging operations in order to cause the anode elements to have a different direction of re-disposition, thereby reducing dendrite growth and anode shape change during recharging operations, and increasing the number of recharging cycles of the metal-fuel card (e.g. greater than 100) as well as the depth-of-discharge (DOD) within the anode structure to increase energy density of the system.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein the segmented cathode construction of the present invention enables improved oxygen transport to the discharging cells thereof to increase the energy density of the system, and also enables improved oxygen evacuation from the recharging cells thereof to increase the energy efficiency of the system.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system having high energy density and low manufacturing cost, using an environmentally friendly technology having diverse applications including, for example, electric vehicles.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein relatively low-current electrical conductors and electronically-controlled power switching circuits are used to selectively recharge particular sections of a loaded metal-fuel structure that have been partially or completely discharged during power generation operations.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein small and electrically isolated electrode elements are used so that currents produced therefrom during discharging operations can be handled using thin current collector structures and low-power rating semiconductor switching elements.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein a plurality of recharging-optimized cathode element structures are electrically-switched into operation for recharging selected regions of discharged metal-fuel in order to attain increased levels of recharging efficiency during recharging operations, while extending the lifetime of the recharging cathode elements in the system.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein a metal-fuel management subsystem is provided for automatically managing the amount of metal-fuel remaining on each indexed region of the metal-fuel structure (e.g. metal-fuel card) being discharged so that, during recharging operations, only the recharging-optimized cathode structures associated with discharged metal-fuel regions are electrically-switched into operation to enable recharging of such metal-fuel regions.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein a metal-fuel management subsystem is provided for automatically managing the amount of metal-oxide remaining on each indexed region of the metal-fuel structure (e.g. metal-fuel card) being recharged so that, during discharging operations, only the discharging-optimized cathode elements associated with recharged metal-fuel regions are electrically-switched into operation to enable discharging of such metal-fuel regions.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein the recharging-optimized cathode elements, in contrast with the discharging-optimized cathode elements, can be realized as gas permeable structures having a microstructure provided with micro-pores of a very small size.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein the discharging-optimized cathode elements, in contrast with the recharging-optimized elements are realized with a microstructure that is optimized for discharging operations.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein each discharging-optimized cathode element within the hybrid discharging/recharging head assembly has the capacity to produce AC output currents using low power rating semiconductor switching elements (e.g. transistors) and inductive elements (e.g. coils), so as to increase the output voltage level.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein each electrical current-carrying conductor element employed in each electrically-isolated cathode element can be made relatively small and thin due to the low current levels produced from each electronically-controlled FCB cell during discharging operations, thus reducing the weight of the electrical current conductors while improving the efficiency of electrical current distribution within the discharging/recharging head assembly.
Another object of the present invention is to provide an improved metal-air FCB system, wherein a first array of anode-contacting elements are provided in spatial registration with a first array of cathode elements (i.e. segments) so as to produce a plurality of low-power discharging cells for loading recharged metal-fuel material therewithin and generating a first quantity of electrical power therefrom during low-power discharging operations, and a second array of anode-contacting elements are provided in spatial registration with a second array of cathode elements (i.e. segments) so as to produce a plurality of high-power discharging cells for loading recharged metal-fuel material therewithin and generating a second quantity of electrical power therefrom during high-power discharging operations.
Another object of the present invention is to provide such an improved metal-air FCB system, wherein the low-power and high-power discharging cells are realized within a unity support structure or subassembly, and each discharging cell is electronically-controllable in order to carry out any one of a number of output power, voltage and/or current control methods under microprocessor control during discharging operations.
Another object of the present invention is to provide an improved rechargeable metal-air FCB system, wherein a first array of anode-contacting elements are provided in spatial registration with a first array of cathode elements (i.e. segments) so as to produce a plurality of low-power recharging cells for loading discharged metal-fuel material therewithin and supplying a first quantity of electrical power thereto during low-power recharging operations, and a second array of anode-contacting elements are provided in spatial registration with a second array of cathode elements (i.e. segments) so as to produce a plurality of high-power recharging cells for loading discharged metal-fuel material therewithin and supplying a second quantity of electrical power thereto during high-power recharging operations.
Another object of the present invention is to provide such an improved rechargeable metal-air FCB system, wherein the low-power and high-power recharging cells are realized within a unity support structure or subassembly, and each recharging cell is electronically-controllable in order to carry out any one of a number of input power, voltage and/or current control methods under microprocessor control during recharging operations.
Another object of the present invention is to provide a metal-air FCB power production module, wherein the discharging load structures comprises a plurality of electrically-activated discharging cells, each being connected in an electrical circuit having a power-switching transistor and an inductive element (e.g. inductive coil) for producing stepped-up voltage levels which are combined in parallel for increased current capacity, and regulated using capacitative elements at the output of the FCB power producing module.
Another object of the present invention is to provide a metal-air FCB module, wherein a switching transistor, assigned to each discharging cell, chops the low-level DC current generated across the discharging cell, thereby producing low-level high-frequency AC currents which are passed through small inductive elements to generate high-frequency voltage signals which are then passed through low-frequency pass filters (i.e. high-frequency rejection filters) to produce stepped-up DC voltages for driving various types of electrical loads.
Another object of the present invention is to provide such a metal-air FCB module, wherein the stepped-up voltages are combined in series and/or parallel, so as to generate a particular output voltage required to meet the electrical loading conditions at any particular instant in time.
Another object of the present invention is to provide a novel battery-type electrical power producing module comprising: a plurality of discharging cells; a plurality of transistor-based power switches, each being connected to one discharging cell and being controlled by a switching controller; and an inductive element configured with at least one discharging cell and at least one transistor-based power switch, for producing a stepped-up output voltage having a DC voltage component and high-frequency signal components; and a low-pass filtering circuit for filtering out high-frequency signal components from stepped-up output voltage.
Another object of the present invention is to provide a novel method of supplying electrical power to an electrical load from a battery-type electrical power producing module having a plurality of discharging cells, comprising the steps of: generating electrical current pulses from each discharging cell; supplying said electrical current pulses to the primary coil of a step-up type voltage transformer to produce a voltage thereacross; generating a stepped up output voltage across the secondary coil of the voltage transformer; and regulating the stepped-up output voltage by rectifying and low pass-filtering the output current generated therefrom.
Another object of the present invention is to provide such a novel method of supplying electrical power to an electrical load, wherein each discharging cell comprises a discharging cathode structure, an anode structure formed from a metal-fuel material, and an ionically-conducting material disposed between the discharging cathode structure and the anode structure; wherein the anode structures of the discharging cells are realized by an unpatterned or patterned sheet of conductive material maintained at a common electrical potential (e.g. electrical ground); and wherein the ionically conductive medium is a shared medium among the discharging cells, not requiring ionic-isolation therebetween.
Another object of the present invention is to provide a battery-type electrical power producing module for supplying electrical power to an electrical load, comprising: a plurality of discharging cells provided along a support substrate; a plurality of power switching elements for generating electrical current pulses from each discharging cell; a step-up type output voltage transformer having at least one primary coil and at least one secondary coil; a plurality of electrical conductors for conducting the electrical current pulses to the at least one primary coil of the step-up type output voltage transformer to produce a stepped up output voltage across the at least one secondary coil, and the stepped up output voltage having time-varying signal components; a rectifier for rectifying electrical current produced from the at least one secondary coil; and a low pass-filtering capacitor for substantially removing the time-varying signal components from said stepped up output voltage while being applied across an electrical load connected in electrical parallel with the low pass filtering capacitor.
Another object of the present invention is to provide such a battery-type electrical power producing module, wherein each discharging cell comprises a discharging cathode structure, an anode structure formed from a metal-fuel material, and an ionically-conducting material disposed between the discharging cathode structure and the anode structure; wherein the anode structures of the discharging cells are realized by an unpatterned or patterned sheet of conductive material maintained at a common electrical potential (e.g. electrical ground); and wherein the ionically conductive medium is a shared medium among the discharging cells, not requiring ionic-isolation therebetween.
Another object of the present invention is to provide a novel method of supplying electrical power to an electrical load from a battery-type electrical power producing module having a plurality of discharging cells, comprising the steps of: generating electrical current pulses from each the discharging cell; supplying the electrical current pulses to an inductive element to produce a stepped-up output voltage across the inductive element; rectifying the output current generated from the inductive element to produce a rectified output current having time-varying signal components; using a low pass-filtering capacitor to remove a significant portion of the time-varying signal components from the rectified output current, while maintaining a substantially constant output voltage across an electrical load connected in electrical parallel with the low pass-filtering capacitor.
Another object of the present invention is to provide such a novel method of supplying electrical power to an electrical load, wherein each discharging cell comprises a discharging cathode structure, an anode structure formed from a metal-fuel material, and an ionically-conducting material disposed between the discharging cathode structure and the anode structure; wherein the anode structures of the discharging cells are realized by an unpatterned or patterned sheet of conductive material maintained at a common electrical potential (e.g. electrical ground); and wherein the ionically conductive medium is a shared medium among the discharging cells, not requiring ionic-isolation therebetween.
Another object of the present invention is to provide a novel battery-type electrical power producing module for supplying electrical power to an electrical load, comprising: a plurality of discharging cells provided along a support substrate; a plurality of power switching elements for generating electrical current pulses from each discharging cell; a plurality of inductive elements connected in electrical series with the plurality of discharging cells, each inductive element producing a stepped-up voltage across each the inductive element in response to the electrical current pulses being supplied therethrough by the discharging cell, and each stepped up voltage having time-varying signal components; at least one rectifier for rectifying electrical current produced from the inductive elements; and a low pass-filtering capacitor for receiving the rectified electrical current and substantially removing the time-varying signal components from the stepped up voltages while an electrical load is connected in electrical parallel with the low pass filtering capacitor.
Another object of the present invention is to provide such a novel method of supplying electrical power to an electrical load, wherein each discharging cell comprises a discharging cathode structure, an anode structure formed from a metal-fuel material, and an ionically-conducting material disposed between the discharging cathode structure and the anode structure; wherein the anode structures of the discharging cells are realized by an unpatterned or patterned sheet of conductive material maintained at a common electrical potential (e.g. electrical ground); and wherein the ionically conductive medium is a shared medium among the discharging cells, not requiring ionic-isolation therebetween.
Another object of the present invention is to provide a novel method of supplying electrical power to an electrical load from a battery-type electrical power producing module having a plurality of discharging cells, comprising the steps of: generating electrical current pulses from each discharging cell; supplying said electrical current pulses to an inductive element configured in electrical series with the discharging cell so as to produce a stepped-up voltage across each the inductive element: rectifying the output current generated from the inductive element to produce a rectified output current having time-varying signal components; and low pass-filtering the rectified output current to remove a substantial portion of the time-varying signal components while maintaining a substantially constant output voltage across an electrical load.
Another object of the present invention is to provide such a novel method of electrical power production, wherein each discharging cell comprises a discharging cathode structure, an anode structure formed from a metal-fuel material, and an ionically-conducting material disposed between the discharging cathode structure and the anode structure; wherein the anode structures of the discharging cells are realized by an unpatterned or patterned sheet of conductive material maintained at a common electrical potential (e.g. electrical ground); and wherein the ionically conductive medium is a shared medium among the discharging cells, not requiring ionic-isolation therebetween.
Another object of the present invention it to provide a novel battery-type electrical power producing module for supplying electrical power to an electrical load, comprising: a plurality of discharging cells provided along a support substrate; a plurality of power switching elements for generating electrical current pulses from each discharging cell; an inductive element for producing an stepped up output voltage in response to the electrical current pulses supplied therethrough; a plurality of electrical conductors for conducting said electrical current pulses to the inductive element to produce the stepped up voltage across said inductive element, said stepped up voltage having time-varying signal components; at least one rectifier for rectifying electrical current produced from each inductive element; and a low pass-filtering capacitor for substantially removing the time-varying signal components from the stepped up voltage while being applied across an electrical load connected in electrical parallel with the low pass filtering capacitor.
Another object of the present invention is to provide such a metal-air FCB power producing module, wherein each discharging cell comprises a discharging cathode structure, an anode structure formed from a metal-fuel material, and an ionically-conducting material disposed between the discharging cathode structure and the anode structure; wherein the anode structures of the discharging cells are realized by an unpatterned or patterned sheet of conductive material maintained at a common electrical potential (e.g. electrical ground); and wherein the ionically conductive medium is a shared medium among the discharging cells, not requiring ionic-isolation therebetween.
Another object of the present invention is to provide such battery-type electrical power producing modules, wherein by producing stepped-up output voltages using low-magnitude switching currents results in a significant decrease in the weight, size, and cost of the battery module in various applications as well as a significant decrease in heat dissipation due to IxR power losses, thus increasing the overall switching efficiency of the resulting battery module while avoiding the need to use large heat sinking structures.
A further object of the present invention is to provide such an improved method of generating electrical power from metal-air fuel cell battery (FCB) systems.
These and other Objects of the present invention will become apparent hereinafter.